Hello Italkian friend! Greetings from Brazil.
Yeah, they do! I may say a lot! African american people from the southwest of the USA, for instance, never use "does" for he/she/it. They usually say: Momma don't know what I do! They may also sometimes say: " You is a good man"!
You see? Speaking correctly might not be only foreigners' trouble!
Let's see something from famous rock bands like the Beatles and the Rolling stones. In the song "Ticket to ride" John and Paul sing: " She's got a ticket to ride but she don't care! (Wouldn't it be, "she doesn't care?)
Another example from Mick Jagger's voice: I can't get no satisfaction! ( wouldn't it be: "I can't get ANY satisfaction"?)
As you can see, sometimes it is not that important to speak English so correctly except you are in a situation that demands you to do so, like an important meeting or an international conference. In short, enjoy the trip, ´cause you're not alone!